Hormone's Effect on the Elderly
Giving elderly people supplements of a hormone that tends to decrease as people age may help prevent weight gain and the increased risk of diabetes that often accompanies aging, according to a preliminary study.
The hormone dehydroepiandrosterone (DHEA) is produced by the adrenal glands. Levels peak at about age 20 and then gradually decline with age.
By the time most people are about 70, their DHEA levels have fallen to only about 20 percent of their peak levels. Scientists have speculated that dropped DHEA levels may help explain many of the effects of aging.
Dennis T. Villareal and John O. Holloszy of Washington University School of Medicine in St. Louis gave 28 men and 28 women ages 65 to 78 either 50 milligrams of DHEA each day or a placebo.
After six months, those getting DHEA had 7.4 percent to 10.2 percent less fat in their abdomens than those getting the placebo, the researchers found. In addition, those getting the hormone appeared to control their blood sugar levels better than those who got the placebo, indicating they may be less likely to develop diabetes. No adverse effects occurred.
"We found in this preliminary study that DHEA reduced abdominal fat and improved insulin sensitivity," the researchers wrote in reporting their findings in this past Wednesday's issue of the Journal of the American Medical Association.
The researchers are conducting a larger study that will evaluate the effects of DHEA over the course of a year.
-- Rob Stein
Different Drugs From Poppies
Scientists have created genetically engineered opium poppies that can barely produce the morphine, codeine and other potent drugs that make the plants so highly prized on the black market. Instead, the gene-altered flowers build up caches of other chemicals that can be used to make new medications, including some that appear to be effective against malaria.
People have used the sticky, opiate-laden latex from poppy plants as a painkiller since the earliest days of civilization. Two of the plants' chemical components -- morphine and codeine -- remain among the most widely used analgesics in medicine today.
And because their chemical structures are so difficult to copy in the laboratory, they are still derived from the flowers, grown in vast pharmaceutical company fields.
Australian plant researcher Philip Larkin and his team knew that poppies make morphine from the simple amino acid tyrosine in a series of 18 steps. At each step, a different enzyme turns one chemical compound into another.
Using a recently developed genetic technique that allows scientists to block the activity of individual enzymes, Larkin's group dammed the synthetic pathway midstream, causing a buildup of the chemical precursors of morphine.
One of the precursors that accumulated at especially high levels, called (S)-reticuline, had already shown promise for a number of conditions ranging from baldness to malaria. The genetically engineered poppies, the Australian team concludes in the Nov. 14 advanced online issue of Nature Biotechnology, should offer drug developers an easy supply of this medicinal raw ingredient.
-- Rick Weiss
Star Gap Is a Puzzler
Using the sensitive infrared spectrograph on NASA's Spitzer Space Telescope, University of Rochester astronomers earlier this year observed the gap, which appears like a moat, surrounding CoKu Tau 4, a young star about 1 million years old.
University of Rochester astronomer Dan Watson, who led the original investigation, said in a telephone interview that the only explanation that appeared to make sense was that a planet -- even younger than the star -- was plowing a trough in the disc and had taken up all the material in the gap.
"All young stars have discs around them, and they tend to be dusty and dense," Watson said. And although "there are many ways to make holes in the discs," he added, most of these methods "will not work in such a short time."
Planets eventually form from the material in dust discs, but not -- at least according to prevailing theories -- so quickly.
Still, Watson said: "It's likely there's a compact object in the disk," and that object is quite likely a planet, perhaps 500,000 years old.
Last week, a second team of University of Rochester astronomers reported that by analyzing Watson's data, they were able to demonstrate that a Saturn-sized planet or larger could have dug the trough surrounding CoKu Tau 4.
The trouble is that nobody can explain how.
"It's very contentious," Watson said, and he doesn't have a hypothesis, either, at least "nothing I would bet the farm on."
-- Guy Gugliotta